I can provide the exact command or steps for your specific situation. [Now released] Restore MKV Format Support - Adobe Community
The most efficient way to handle multiple streams is using the yt-dlp command-line tool . Unlike standard downloaders, it can merge all available "side" data into one file. Download stream (3) mkv
Are you comfortable using tools, or do you prefer a visual interface ? What operating system (Windows, Mac, Linux) are you using? I can provide the exact command or steps